Late Oligocene Birth of the Modern Pearl River: New Insights From Landscape Evolution Modeling

The Pearl River, originating from the southeastern Tibetan Plateau and transporting substantial sediments into the northern South China Sea, records the coupled influence of tectonics, climate, and surface processes in East Asia. However, the timing and mechanisms of its reorganization remain debated. Here we use the landscape evolution model Badlands to explore hypotheses for the Pearl River's drainage history since the Cenozoic, incorporating reconstructions of dynamic topography, lithospheric deformation, and surface processes. Our simulations suggest that the early Cenozoic landscape of South China was westward‐tilted with a paleo‐coastline ∼300 km south of its present‐day location, where the western tributaries and the paleo‐Pearl River evolved independently. Intensified precipitation associated with the East Asian monsoon may have promoted headward erosion and drainage integration, establishing a Pearl River–scale network at the end of the Late Oligocene. Models with overestimated precipitation produce premature sediment flux peaks, whereas stepwise precipitation increases reproduce the timing of river integration inferred from detrital zircon provenance shifts. Dynamic topography and tectonic forcing shaped the broader landscape but played a secondary role compared to precipitation in controlling drainage development. Although Badlands simplifies fluvial and hillslope processes, the experiments provide testable hypotheses for the climate–tectonics–surface‐process coupling that drives the evolution of large monsoon‐influenced river systems.